1. Field of the Invention
The present invention relates to a composition for the production of artificial marble or granite. The invention also relates to a procedure for transforming this composition into artificial marble or granite and to the artificial marble and granite thus obtained.
2. Description of the Background
Articial marble and granite in block or panel form, generally composed of a mineral filler dispersed in a polymer matrix, are already known in the art, and are described, for example, in U.S. Pat. No. 4.698.010, DE 2.054.168 and Italian patent 1.056.388. A polyester resin or a polymethyl methacrylate are generally used for the purpose, mixed with the inorganic filler and the mixture is subjected to hardening after undergoing compaction. Unfortunately when a polyester resin is used, the product cannot be used externally because of its limited aging resistance, especially when exposed to UV radiation, whereas when a polymethyl methacrylate is used, the disadvantages are basically due to the use of a volatile and toxic polimerizable monomer.
Artificial marble composed of the product of the polymerization of a poly(allyl carbonate) has also been described in the art. In particular, in Japanese Patent Application 61-111-953 an artificial marble is described, composed of the polymerization product of a poly(allyl carbonate) of a polyol containing, as a mineral filler, a fine silica or hydrated alumina powder. In particular, the particle size of the mineral filler varies from 1 to 30 .mu.m, preferably from 5 to 20 .mu.m. Japanese Patent Application 63-237.989 describes a composition for the production of artificial marble composed of a bis(allyl carbonate), containing an oligomer of a di- or tri-hydroxylic alcohol, and an inorganic filler. In particular, the inorganic filler is in the form of particles of 1 to 30 .mu.m in size, preferably from 5 to 10 .mu.m. Japanese Patent Application 63-246.660 describes an artificial marble including a resinous binder and a balloon-shaped inorganic filler, where the inorganic filler is in the form of particles of 10 to 100 .mu.m in size. Finally, Italian Patent Application 19.814 A/90, filed on Mar. 23, 1990, in the name of the Applicant, describes an artificial marble with improved coloring and scratch resistance, composed of the polymerization of a poly(allyl carbonate) of a polyol containing cristobalite as the mineral filler. In particular, the particle size of the mineral filler varies from 1 to 200 .mu.m, preferably from 2 to 50 .mu.m. This artificial marble with a poly(allyl carbonate) binder, has an improved aging resistance. However, high quantities of organic binder are required, making the procedure costly and consequently hindering the commercial development of the product.